line driver?

[ncc74656 2]

My deck is rated at 4 volt preamp but when I measured it I get 4.1 volts at maximum volume on my subwoofer RCA and 0.7 volt on my front and rear. The deck manual States 4 volt at 10 percent Distortion so my question is should I pick up a 3-way line driver, cap the deck volume at three quarters, and use the line driver to boost the one volt and 3 volt signal up to 6 volt?

[lithium 358]

why do you think you need 6 volt? 

[ncc74656 2]

well some arbitrary voltage above .7 with out clipping...

the higher the input the less chance I have of clipping the signal no?

Edited October 7, 2013 by ncc74656

[pmureika 31]

It's higher then 4 volts

[shizzzon 461]

No.. 

 

You have less chance of clipping by Keeping the Input Voltage below maximum input sensitivity.

 

As long as the preout voltage is greater than the minimum input sensitivity range which on most amps is 150-250mv, then you are fine.

 

that is what the gain is for on the amp at this point.

 

Unless you have unwanted noise being produced in the amp because the gain needs to be on max for it to work effectively then line driver never necessary.

 

Line drivers are typically used when running many many many amps off the same output section..

[ncc74656 2]

I have 4 amps on one right now going through a kx3. the gains are 3/4-7/8 up to get output to my speakers and the deck needs to be at 8/9th volume to get loud. 1/2-5/8 volume the engine noise drowns out some of the music. That's why I was thinking getting a line driver and pushing the voltages up to 4 or 5 would greatly help my system as the deck would only need to go up to maybe half volume to get the same amount of output.

[Impious 1,476]

You are missing the point. If your preamp voltage is enough to drive the amplifier to full output, then the voltage output is fine. Gain and volume position are irrelevant here. If you are driving the amp to full output at 90% of max volume and you increase the voltage so you get full output at 50% of max volume...you didn't gain any volume, it just happens sooner in the volume range. Trying to turn the volume knob higher will just result in clipping. It will be "louder", but you'll be driving the equipment into clipping. You aren't gaining anything, other than a loss of range of the volume control.

First thing to determine is if you are diving the amps to full output.

And what do you mean by engine noise? The sound of the engine itself or engine whine through the stereo?

[ncc74656 2]

the sound of the engine itself. there is no wine. I'm worried that I'm gaining the stereo into clipping by having to max its volume to get output.

[lithium 358]

sounds like a sound deadening issue

Edited October 8, 2013 by lithium

[///M5 2,833]

the sound of the engine itself. there is no wine. I'm worried that I'm gaining the stereo into clipping by having to max its volume to get output.

That is all unrelated. If you can turn your gain up further then if you are already clipping that is a USER problem, not a system problem. Only reason then it is clipping is that you have chosen to run the gains too hot. Engine noise is NOT the noise you should be concerned with if your gain is set high. That noise would be thermal and is mostly 1/f noise.

A line driver in your case would be a SERIOUS waste of money.

First step is fix your grounds. They are jacked.

[ncc74656 2]

what makes you think the grounds are jacked? they are bolted to the frame.

I have 200 sqft of fat mat in the cab. the engine is just loud. no amount of dyno can block it.

my understanding is that you can only amp a signal so much. that's why you want a higher pre amp, so you have note headroom. the deck starts to clip the rca signal at 52 of 62 volume. that's about .55v out of the rca. so if I line drive that .55 to 4v then I won't be clipping and can have lower gains on the amps.

am I misunderstanding something here?

p.s. M5 we are both in mn. I should buy you lunch and you can come unjack my system

[///M5 2,833]

what makes you think the grounds are jacked? they are bolted to the frame.

Your comments above. The only one that made sense was noise bothering you. Some portion of your system is not grounded in the way it needs to be if that is happening.

I have 200 sqft of fat mat in the cab. the engine is just loud. no amount of dyno can block it.

Fat Mat is NOT a sound barrier. Sucks ass at it. That is for stopping panel resonance. Using 200 sqft is overkill and NOT beneficial. You need a barrier to cover the car, not the deadener.

my understanding is that you can only amp a signal so much. that's why you want a higher pre amp, so you have note headroom. the deck starts to clip the rca signal at 52 of 62 volume. that's about .55v out of the rca. so if I line drive that .55 to 4v then I won't be clipping and can have lower gains on the amps.

am I misunderstanding something here?

You mean your misconception.

"Amping it so much" has nothing to do with the signal and is only related to how much voltage an amp can supply. If a .7v input will allow the amp to output ALL of it's voltage without noise there is no benefit in raising the input voltage. In fact personally I'd rather use the higher quality portion to gain whatever the signal was. This could surely mean in your case that the amp is better off turned up a bunch than to be fed a dirty signal.

Line Drivers are ONLY useful when you have a shortage of voltage. This will always be displayed by noise or the incapability to actually do what the amp was supposed to do. *excluding line drivers that give zone control for particular applications where differing zone levels need to be dynamically changeable

Buying an LD, from what you've told us, would be a ridiculously huge waste of your money.

[ncc74656 2]

im not following how grounding will lessen engine noise?

 

the fatmat did remove quite a bit of road noise when i installed it, that said im not sure ive ever used a "barrier" like what you are talking about. is that the thick foam stuff?

 

one of the thoughts behind the line driver was that my eclipse is at 100% gain and my deck at max volume still does not max my door speakers. i was under the assumption that the amp was getting 4V untill i tested it a couple days ago. perhaps this is a reason for my poor performance in that regard. i would like to be able to max my amps potential at a lower deck volume to avoid distortion. that part still makes sense to me.

 

im going to borrow a line driver tomorrow from a buddy and play with it, see how it effects things. its an EQ with a line built in so i get to play a bit with tuning as well. i also checked my sub voltage one more time and i had +4 on the deck for the sub, when i removed this my sub rca voltage dropped to 3V, even at max volume.

[lithium 358]

m5 thinks you have a bad ground which is causing weak signal.

 

a barrier would be mlv, check out sounddeadenershowdown.com, great resource for deadening.

 

given your gain and volume settings you either have a fucked install or you system isn't capable of producing enough output.

 

again, you dont understand how the gain on the amp works.  http://www.bcae1.com/gaincon2.htm

[ncc74656 2]

ahha.  now as for ground, what would cause the sub rca to have 3v and the front/rear .5? a ground couldn't do that?

 

so my nest step before anything else should be to see if my head unit is clipping the rca signal before the amp gets to full power. right?

 

oscope the RCA to find that out?

[///M5 2,833]

No, you have engine noise. 99.999% of the time that is a grounding issue.

If your amp isn't a complete fucking piece of shit it is fine with less than a 1V signal. Seriously.

"Maxing" out your door speakers is somewhat unrelated to your amp or headunit. You'd be surprised how little power can make a drive go into over excursion at a particular frequency.

Most likely your settings are all completely jacked, you have unrealistic expectations, or your front stage amp is too small. WAY better to spend the money selling your amp and buying new than to use a line driver.

It is really hard to help you when you don't share details. You are obviously confused, being misled significantly by others (whether it be people or websites) and have come to a false conclusion and are going to go that route no matter what gets said. It'd be WAY healthier for you to take a step back, spend some time on a post and really relay what is going on, how you are currently setup, and what your concerns are.

[Quentin Jarrell 671]

No, you have engine noise. 99.999% of the time that is a grounding issue.

If your amp isn't a complete pucking piece of shit it is fine with less than a 1V signal. Seriously.

"Maxing" out your door speakers is somewhat unrelated to your amp or headunit. You'd be surprised how little power can make a drive go into over excursion at a particular frequency.

Most likely your settings are all completely jacked, you have unrealistic expectations, or your front stage amp is too small. WAY better to spend the money selling your amp and buying new than to use a line driver.

It is really hard to help you when you don't share details. You are obviously confused, being misled significantly by others (whether it be people or websites) and have come to a false conclusion and are going to go that route no matter what gets said. It'd be WAY healthier for you and your pocket book to take a step back, spend some time on a post and really relay what is going on, how you are currently setup, and what your concerns are.

[ncc74656 2]

I don't have any engine noise in my speakers.

the way I have conveyed it here is how it was explained to me by some local shops.

what kind of details would you like ? a step by step of my system setup?

[Impious 1,476]

im not following how grounding will lessen engine noise?

 

the fatmat did remove quite a bit of road noise when i installed it, that said im not sure ive ever used a "barrier" like what you are talking about. is that the thick foam stuff?

 

one of the thoughts behind the line driver was that my eclipse is at 100% gain and my deck at max volume still does not max my door speakers. i was under the assumption that the amp was getting 4V untill i tested it a couple days ago. perhaps this is a reason for my poor performance in that regard. i would like to be able to max my amps potential at a lower deck volume to avoid distortion. that part still makes sense to me.

 

im going to borrow a line driver tomorrow from a buddy and play with it, see how it effects things. its an EQ with a line built in so i get to play a bit with tuning as well. i also checked my sub voltage one more time and i had +4 on the deck for the sub, when i removed this my sub rca voltage dropped to 3V, even at max volume.

To block noise you need mass. It's that simple. Foam absorbs sound, mass blocks it. The thickness of the foam is directly related to the bandwidth of frequencies it absorbs. For low frequencies, such as engine and road noise, foam would have to be unrealistically thick (several feet thick). So instead you want to block it with mass. Mass loaded vinyl is about the easiest way to go about it. Read some of Don's info on the sound deadened showdown website. Of course road noise went down some with 200sqft of CLD...it has mass so it's going to block some noise although it's still relatively ineffective. If your engine is really THAT loud, covering the truck in MLV with a decoupling layer of foam is a worthwhile investment. Double mass and sound transmission decreases by 6db. That's a huge difference.

In car audio people always preach the "high gain is bad" mantra to keep noobs from just maxing it out every time, but as a "rule" it's a myth. Most amps are designed to produce full output with as little as .2V, and the gain is there to allow the amplifier to output full power without being overdriven with a wide range of voltages...as low as .2V. Aside from thermal noise M5 mentioned, gain position and distortion are not related in the way you appear to believe they are. As long as the gain is properly set for the input voltage, distortion is not affected. Whomever told you otherwise is mistaken. It seems you need to stop listening to the local shops if that is who's telling you this. Setting the gain high with a low input voltage is exactly how the amp was designed and what the gain is there for.

Be careful "playing around" with a line driver. Aside from the ability to drive both the outputs and/or the inputs of the amp into severe clipping, many people either don't readjust the gain and other setting to compensate for the higher voltage or they don't properly readjust the gain and other settings and fool themselves into thinking they gained something when in reality they simply fucked up the system settings and aren't comparing the changes correctly.

[ncc74656 2]

as i have gone through the websites reading about gain i would agree that i was mistaken on how it functioned. the "rule" you speak of was told to me by circuit city and was in there training programs when i worked there and was recited by many shops i have gone to over the years. "higher gain leads to distortion, thats why you want a head unit with 4 or 5V pre amps so you get good, clean, and undistorted signal to your amps"  so thats what ive been running with untill now. 

 

my goal is not to eliminate road noise, the tires are 37" with 1.5" tread depth, they alone will be loud enough to enter the cab but you can not hear them over the engine.

MAYBE at some point i might add some more but its not a priority for me.

 

this is the engine sound i am talking about, first video is driving down the road and second is starting sound: 

 

 

engine starting > 

 

i dont know why youtube screwed up the video on starting but it gets the idea across.

Edited October 9, 2013 by ncc74656

[Impious 1,476]

Deadening the cab will reduce engine noise....road noise was generic for sound that enters the cab while driving, engine and exhaust included.

If part of your issue to getting the speaker volume you want is engine noise, I'd make it a priority. Every decibel of noise you block is a decibel of volume you'll gain.

[///M5 2,833]

A well installed barrier will be the BEST money you've spent on your stereo.

[///M5 2,833]

And btw, since I live here I'll tell you a secret. From my knowledge there is not an audio shop here where I would actually listen to their opinion. Probably an exception, but I've been in a few and they are awful.

[Quentin Jarrell 671]

I have personally only seen two vehicle that needed line drivers and it was not for voltage reason but for current reasons.  One was the Packed Rat by Prestige sounds and customs.  It had a shit ton of amps and the headunit could not supply enough current to power the inputs.  The second was my vehicle which was a mustang with (12) 12 inch rockford T2's.  It had (12) 2,000 watt amps for bass, (3) amps for highs and a 125watt x 4 that was used as a line driver.  The output on the amp was modified so that it produced 6 volts out but was capable of sending enough current to all the amps without making them shut down due to too low of a signal.

[ncc74656 2]

got ya. well i will be doing body work in the spring so thats when i would do anything with more sound deadening. 

 

i figured out one issue with my setup. i had my remote bass knob plugged in when i was tuning. so the gain was always at its minimal level. i had thought this knobb was for bass boost and did not realize it was linked to the gain settings.